SRP (stands for software rendering pipeline) is an OpenGL-like CPU graphics library written in C with minimal dependencies. It was made as a hobby programming project. The source code (and more information) is available on Github.

A nice way to get familiar with API is to read Examples or API reference. If you are interested in implmentation details, see Internal documentation.

Here is a graph overviewing the pipeline: (red edges - the main path from a draw call to a fragment on the screen, green nodes - objects created by user)